http://www.williamsons.com/

These guys will take your Sun tach-or sell you one from their stck- and make it into anything you want. I purchased a 4 grand scale Sun tach from them (old International tach) and had them convert it to 6 volt positive ground. They can adapt it to 4-6-8 cylinders (probably 12 if ya got 'em!) There is no need for a seperate sender one they have converted the tach.